Absorbent articles for personal hygiene, such as baby diapers, training pants for toddlers, feminine pads and adult incontinence undergarments, are designed to absorb and contain body exudates, in particular large quantity of urine. These absorbent articles comprise several layers providing different functions, for example a topsheet, a backsheet and an absorbent core positioned between the topsheet and backsheet, among other layers. The key functions of the absorbent core are to absorb and retain the exudates for a prolonged period of time, for example overnight for a diaper, to minimize re-wet to keep the wearer dry and to avoid soiling of clothes or bed sheets.
The majority of currently marketed absorbent articles comprise as absorbent material a blend of comminuted wood pulp with superabsorbent polymers (SAP) in particulate form, also called absorbent gelling materials (AGM), for example as disclosed in U.S. Pat. No. 5,151,092 (Buell). The SAP provides most of the absorbent capacity while the cellulose fibers can serve to immobilize the SAP within the core. Absorbent cores consisting essentially of SAP without cellulose fibers (also airfelt-free cores) have been proposed for example in WO2004/071539 (Busam), WO2008/155699 (Hundorf), WO95/11652 (Tanzer) or WO2012/052172 (Van Malderen). Removing the cellulose fibers has the advantage of providing thinner cores, but creates new challenges in terms of immobilization of the SAP in dry and wet state. This problem has been addressed in Busam and Hundorf by spraying a fiberized hot-melt thermoplastic material on a discontinuous SAP layer. These documents also consider using an auxiliary glue to improve the adhesion of the thermoplastic material to the substrate layer. More recently, WO2010/027719 (Hundorf) disclosed an improved process for making such cellulose free absorbent core using a plurality of cross-bars.
There is a continuous need for providing improved absorbent cores that balance absorbency performance with material saving. The present invention provides an improvement to the previously proposed cores having little or no cellulose fibers. The absorbent structures and cores of the invention have a profiled absorbent material distribution to provide higher amount of absorbent material where it is most needed, typically towards the crotch and to a lesser extent front of the absorbent structure or core, while eliminating or at least substantially reducing the auxiliary glue in the zones having low amount of absorbent material, typically towards the back of the absorbent structure and/or towards the front of the structure. This combination of features provides a reduction of adhesive usage while maintaining high absorbency performance and good dry and wet SAP immobilization properties.